Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015 Fund	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Number of mutual funds that invest in debt securities or loans that qualify for credit under the Community Reinvestment Act	4
Redemption notice required to be given to convert capital account, number of days	60 days
Recurring [Member]
Investment securities available-for-sale [Abstract]
U.S. Treasury notes	72,078	$ 62,560
U.S. Agency notes	92,216	83,637
U.S. Agency mortgage-backed securities	30,504	38,032
Certificates of deposit with other banks	2,589	3,086
Municipal securities:
Non-taxable	81,212	77,395
Taxable	17,669	16,395
Mutual funds	2,481	2,461
Trust preferred securities	50	50
Equity securities	1,728	1,749
Total recurring fair value measurements	300,527	285,365
Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Investment securities available-for-sale [Abstract]
U.S. Treasury notes	72,078	62,560
U.S. Agency notes	0	0
U.S. Agency mortgage-backed securities	0	0
Certificates of deposit with other banks	0	0
Municipal securities:
Non-taxable	0	0
Taxable	0	0
Mutual funds	1,481	1,461
Trust preferred securities	50	50
Equity securities	1,728	1,749
Total recurring fair value measurements	75,337	65,820
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Investment securities available-for-sale [Abstract]
U.S. Treasury notes	0	0
U.S. Agency notes	92,216	83,637
U.S. Agency mortgage-backed securities	30,504	38,032
Certificates of deposit with other banks	2,589	3,086
Municipal securities:
Non-taxable	81,212	77,395
Taxable	17,669	16,395
Mutual funds	1,000	1,000
Trust preferred securities	0	0
Equity securities	0	0
Total recurring fair value measurements	225,190	219,545
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Investment securities available-for-sale [Abstract]
U.S. Treasury notes	0	0
U.S. Agency notes	0	0
U.S. Agency mortgage-backed securities	0	0
Certificates of deposit with other banks	0	0
Municipal securities:
Non-taxable	0	0
Taxable	0	0
Mutual funds	0	0
Trust preferred securities	0	0
Equity securities	0	0
Total recurring fair value measurements	0	0
Nonrecurring [Member]
Nonrecurring fair value measurements:
Impaired loans	4,801	4,872
Other real estate owned and repossessed assets	1,364	1,370
Total nonrecurring fair value measurements	6,165	6,242
Nonrecurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Nonrecurring fair value measurements:
Impaired loans	0	0
Other real estate owned and repossessed assets	0	0
Total nonrecurring fair value measurements	0	0
Nonrecurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Nonrecurring fair value measurements:
Impaired loans	0	0
Other real estate owned and repossessed assets	0	0
Total nonrecurring fair value measurements	0	0
Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Nonrecurring fair value measurements:
Impaired loans	4,801	4,872
Other real estate owned and repossessed assets	1,364	1,370
Total nonrecurring fair value measurements	6,165	$ 6,242

No definition available.

Name:	lcnb_AvailableForSaleMutualFundsFairValueDisclosure
Namespace Prefix:	lcnb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in equity securities which are categorized as Available-for-sale.

+ References

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

+ References

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

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No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

+ References

No definition available.

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- Definition

Fair value portion of a savings certificate entitling the Entity (that is, bearer) to receive interest at an established maturity date, based upon a fixed interest rate.

+ References

No definition available.

+ Details

Name:	lcnb_CertificateOfDepositFairValueDisclosure
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair Value, Investments, Redemption Notice Required to be Given to Convert Capital Account, Period

+ References

No definition available.

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Name:	lcnb_FairValueInvestmentsRedemptionNoticeRequiredtobeGiventoConvertCapitalAccountPeriod
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- Definition

This element represents the fair value disclosure of impaired loans that have had a fair value adjustment since their initial recognition.

+ References

No definition available.

+ Details

Name:	lcnb_ImpairedLoansFairValueDisclosure
Namespace Prefix:	lcnb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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Name:	lcnb_MunicipalSecuritiesAbstract
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- Definition

Represents the number of mutual funds that invest in debt securities or loans that qualify for credit under the Community Reinvestment Act.

+ References

No definition available.

+ Details

Name:	lcnb_NumberOfMutualFundsThatInvestInDebtSecuritiesOrLoansThatQualifyForCreditUnderCommunityReinvestmentAct
Namespace Prefix:	lcnb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

This element represents the fair value disclosure of other real estate owned and valued at fair value upon transfer from loans. These items are marked down to fair value at the time they are transferred from loans.

+ References

No definition available.

+ Details

Name:	lcnb_OtherRealEstateOwnedAndRepossessedAssetsFairValueDisclosure
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Data Type:	xbrli:monetaryItemType
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- Definition

+ References

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

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No definition available.

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Namespace Prefix:	lcnb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

+ References

No definition available.

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Namespace Prefix:	lcnb_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a nonrecurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

No definition available.

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- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a recurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

No definition available.

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Balance Type:	debit
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